<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <script>
        //设置变量接收用户输入数据,记得隐式转化一下接收来的数值
        let num = +prompt('输入一个1~3的数')
        // 判断,switch的判断是===
        switch (num) {
            case 1:
                alert('你点击的是1')
                break
            case 2:
                alert('你点击的是2')
                break
            case 3:
                alert('你点击的是3')
                break
            default:
                alert('输入的数不符合规则')
        }
    </script>
</body>

</html>